Display device and driving method thereof

ABSTRACT

The present disclosure provides a display device including a controlling unit, a display driver, a sensor driver, a display element, and a sensor element. The display driver and the sensor driver are electrically connected to the controlling unit respectively. The display element is electrically connected to the display driver, and the sensor element is electrically connected to the sensor driver. When the sensor element is sensing a biometric feature in a sensing time period, the display element is refreshed by the display driver 3 to 120 times in the sensing time period.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure relates to a display device and a driving methodthereof, and more particularly, to a display device having biometricsensors and a driving method thereof.

2. Description of the Prior Art

The growing demand for information security and information privacy hasdriven use of biometric authentication on electronic devices such assmartphones, laptops, tablets, banking devices, and gaming consoles. Apopular form of biometric authentication is fingerprint identification.Recently, fingerprint sensors have been adopted by various electronicdevices so that the electronic devices can be unlocked by device ownersvia fingerprint authentication, protecting the electronic devices fromunauthorized access.

Conventionally, just for an example, a fingerprint sensor is providedseparately from a display panel in a display device, so a screen-lockeddisplay device can be unlocked by simply touching the fingerprintsensor. Nevertheless, it is of great interest to display devicemanufacturers and users to combine the fingerprint sensor into thedisplay panel, thereby increasing the screen-to-body ratio of thedisplay device and offering a narrow-border or bezel-less design.However, it is difficult to add the fingerprint sensor into the displayregion without losing the resolution of the display device, and when thefingerprint sensor is disposed in the display region, the area of thefingerprint sensor will be too small, resulting in bad sensitivity.

SUMMARY OF THE DISCLOSURE

According to an embodiment, a display device is disclosed and includes acontrolling unit, a display driver electrically connected to thecontrolling unit, a sensor driver electrically connected to thecontrolling unit, a display element electrically connected to thedisplay driver, and a sensor element electrically connected to thesensor driver. When the sensor element is sensing a biometric feature ina sensing time period, the display element is refreshed by the displaydriver 3 to 120 times in the sensing time period.

According to another embodiment, a driving method of a display device isdisclosed and includes the following steps. First, a display controlsignal is provided to a display driver and a sensor control signal isprovided to a sensor driver by a controlling unit. Next, a displaydriving signal is transmitted to a display element by the displaydriver. Then, a sensor driving signal is transmitted to a sensor elementby the sensor driver, wherein when the sensor element is sensing abiometric feature in a sensing time period, the display element isrefreshed by the display driver 3 to 120 times in the sensing timeperiod.

These and other objectives of the present disclosure will no doubtbecome obvious to those of ordinary skill in the art after reading thefollowing detailed description of the embodiment that is illustrated inthe various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a block diagram of a display deviceaccording to an embodiment of the present disclosure.

FIG. 2 schematically illustrates a top view of a display deviceaccording to this embodiment of the present disclosure.

FIG. 3 and FIG. 4 schematically illustrate sectional views of displayelements and sensor elements according to some embodiments of thepresent disclosure.

FIG. 5 schematically illustrates a top view of an arrangement of thesub-pixels and the sensing units according to some embodiments of thepresent disclosure.

FIG. 6 schematically illustrates a flowchart of a driving method of thedisplay device for identifying the biometric feature according to thisembodiment of the present disclosure.

FIG. 7 schematically illustrates timing sequences of the display controlsignal, the sensor control signal, the display scan signal, the sensingscan signal and the readout signal.

FIG. 8 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure.

FIG. 9 schematically illustrates sub-pixels turned on in different frametimes according to some embodiments of the present disclosure.

FIG. 10 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure.

FIG. 11 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure may be understood by reference to the followingdetailed description, taken in conjunction with the drawings asdescribed below. It is noted that, for purposes of illustrative clarityand being easily understood by the readers, various drawings of thisdisclosure show a portion of the electronic device, and certain elementsin various drawings may not be drawn to scale. In addition, the numberand dimension of each element shown in drawings are only illustrativeand are not intended to limit the scope of the present disclosure.

Certain terms are used throughout the description and following claimsto refer to particular elements. As one skilled in the art willunderstand, electronic equipment manufacturers may refer to an elementby different names. This document does not intend to distinguish betweenelements that differ in name but not function. In the followingdescription and in the claims, the terms “include”, “comprise” and“have” are used in an open-ended fashion, and thus should be interpretedto mean “include, but not limited to . . . ”.

It will be understood that when an element or layer is referred to asbeing “disposed on” or “connected to” another element or layer, it canbe directly on or directly connected to the other element or layer, orintervening elements or layers may be presented (indirectly). Incontrast, when an element is referred to as being “directly on” or“directly connected to” another element or layer, there are nointervening elements or layers presented.

In addition, in this specification, relative expressions may be used.For example, “lower”, “bottom”, “higher” or “top” are used to describethe position of one element relative to another.

Although terms such as first, second, third, etc., may be used todescribe diverse constituent elements, such constituent elements are notlimited by the terms. The terms are used only to discriminate aconstituent element from other constituent elements in thespecification. The claims may not use the same terms, but instead mayuse the terms first, second, third, etc. with respect to the order inwhich an element is claimed. Accordingly, in the following description,a first constituent element may be a second constituent element in aclaim.

As used herein, the term “connected to” or “coupled to” that is used todesignate a connection or coupling of one element to another elementincludes both a case that an element is “directly connected or coupledto” another element and a case that an element is “electronicallyconnected or coupled to” another element via still another element.

It should be noted that the technical features in different embodimentsdescribed in the following can be replaced, recombined, or mixed withone another to constitute another embodiment without departing from thespirit of the present disclosure.

FIG. 1 schematically illustrates a block diagram of a display deviceaccording to an embodiment of the present disclosure. The display device1 can both display image and identify biometric feature in its displayregion. For example, the display device 1 may be a smartwatch, asmartphone, a tablet or a display device having an in-display biometricsensor, but not limited thereto. In another embodiment, the displaydevice 1 also could be used for tiling another display device to form atiling electronic device. As shown in FIG. 1, the display device 1 ofthis embodiment includes a controlling unit 10, a display driver 12, asensor driver 14, a display element 16, and a sensor element 18. Thedisplay driver 12 and the sensor driver 14 are electrically connected tothe controlling unit 10 respectively, so the controlling unit 10 canrespectively provide a display control signal DC to the display driver12 and provide a sensor control signal SC to the sensor driver 14 forseparately controlling on/off state of the display driver 12 and on/offstate of the sensor driver 14. The controlling unit 10 may be forexample an image processor, a digital signal processor, a centralprocessing unit (CPU), a microprocessor or other suitable device.Furthermore, the display element 16 is electrically connected to anddriven by the display driver 12, and the sensor element 18 iselectrically connected to and driven by the sensor driver 14. Afterreceiving the display control signal DC, the display driver 12 cantransmit a display driving signal DDS to the display element 16 to turnon the display element 16; similarly, after receiving the sensor controlsignal SC, the sensor driver 14 can transmit a sensor driving signal SDSto the sensor element 18 to turn on the sensor element 18. The displayelement 16 is used for displaying image on screen or generating lightfor biometric feature identification; for example, the display element16 may include sub-pixels of self-emissive display panel, such as anorganic light-emitting diode (OLED) display panel, or an inorganic LED(such as quantum-dot LED, Mini-LED, or Micro-LED) display panel, orsub-pixels of non-self-emissive display panel, such as a liquid crystaldisplay panel. The sensor element 18 is used for receiving reflectedlight from the biometric feature, so as to capture information (such asan image) of the biometric feature. The sensor element 18 may be forexample a fingerprint sensor or other kind of image sensor, but notlimited thereto.

In this embodiment, the display device 1 may optionally further includea processing unit 24, and the controlling unit 10 is electricallyconnected to the display driver 12 and the sensor driver 14 through theprocessing unit 24. The function of the processing unit 24 may be thesame as or similar to the function of the controlling unit 10, but notlimited thereto. For example, the processing unit 24 can drive oroperate the display driver 12 and drive the sensor driver 14, and thenread signals from the sensor element 18 out. In such case, thecontrolling unit 10 may not only be used to drive the display driver 12,the sensor driver 14, the display element 16 and the sensor element 18,but also other devices. Thus, when the area of the display element 16and the sensor element 18 is large, the data needed to process is huge,which may reduce the signal processing speed of the controlling unit 10.By means of the processing unit 24 designed to process signals inadvance, the load of the controlling unit 10 can be shared with theprocessing unit 24. The signal processing speed of the display device 1may be enhanced accordingly. In such situation, the display controlsignal DC and the sensor control signal SC may be provided from theprocessing unit 24. In some embodiment, the display driver 12, thesensor driver 14 and the processing unit 24 may be integrated into asingle integrated circuit 25 that may be bonded on an array substrate ofthe display device 1, and the display element 16 and the sensor element18 may be electrically connected to the single integrated circuit 25through wires, but not limited thereto. In some embodiments, the displaydevice 1 may not include the processing unit 24.

The display driver 12 may include a gate driver 121 and a data driver122 for driving the display element 16. The gate driver 121 may providescanning signals for turning on the display element 16, and the datadriver 122 may provide display signals to the display element 16, suchthat the display element 16 can display the desired image. For example,the gate driver 121 may include shift register unit, logic unit, levelshift unit and/or digital buffer unit, and the data driver 122 mayinclude shift register unit, level shift unit, digital to analogconverter (or multiplexer) and/or analog buffer unit, but not limitedthereto. The sensor driver 14 may include another gate driver 141 and areadout driver 142 for signal readout of the sensor element 18. The gatedriver 141 may provide scanning signals for turning on the sensorelement 18, and the readout driver 142 may receive readout signals fromthe sensor element 18, such that the signals detected by the sensorelement 18 can be read out. In some embodiments, the gate driver 121,the data driver 122, the gate driver 141 and/or the readout driver 142may be formed in the array substrate of the display device 1 bythin-film transistor process, but not limited thereto. In someembodiments, the gate driver 121, data driver 122, the gate driver 141and/or the readout driver 142 may be formed in one or more integratedcircuit and be bonded on the array substrate or a flexible printedcircuit substrate that adheres to the array substrate.

In this embodiment, the display driver 12 may optionally further includea timing control unit 123 electrically connected to the gate driver 121and the data driver 122 to provide timing signals to the gate driver 121and the data driver 122 respectively, and the gate driver 121 and thedata driver 122 are electrically connected to the controlling unit 10 orthe processing unit 24 through the timing control unit 123. In someembodiments, the timing control unit 123 may be disposed outside thedisplay driver 12 but still be electrically connected between the gatedriver 121 and the controlling unit 10 or the processing unit 24 andbetween the data driver 122 and the controlling unit 10 or theprocessing unit 24.

In this embodiment, the sensor driver 14 may optionally further includeanother timing control unit 143 electrically connected to the gatedriver 141 and the readout driver 142 to provide timing signals to thegate driver 141 and the readout driver 142 respectively, and the gatedriver 141 and the readout driver 142 are electrically connected to thecontrolling unit 10 or the processing unit 24 through the another timingcontrol unit 143. In some embodiments, the another timing control unit143 may be disposed outside the sensor driver 14 but still beelectrically connected between the gate driver 141 and the controllingunit 10 or the processing unit 24 and between the readout driver 142 andthe controlling unit 10 or the processing unit 24.

In some embodiments, the timing control unit 123 and the another timingcontrol unit 143 may be integrated into one timing control unit outsidethe display driver 12 and the sensor driver 14, and the integratedtiming control unit may electrically connect the display driver 12 andthe sensor driver 14 to the controlling unit 10 or the processing unit24 respectively, thereby reducing the number of the timing controlunits. Since the display driver 12 and the sensor driver 14 arecontrolled by the same one timing control unit, the possibility oftiming disorder or timing error can be reduced. Also, when theprocessing unit 24, the integrated one timing control unit, the displaydriver 12 and the sensor driver 14 are integrated into one integratedcircuit, the size of the integrated circuit can be decreased, and theborder width of the display device 1 for disposing the integratedcircuit can be narrowed. In some embodiments, the integrated one timingcontrolling unit and the processing unit 24 may be integrated into asingle integrated circuit while the display driver 12 and the sensordriver 14 are not integrated into the single integrated circuit.

In some embodiments, the display device 1 may further include a touchsensing element (not shown in figures) for sensing the position of thebiometric feature. The touch sensing element may be electricallyconnected to the controlling unit 10 or the processing unit 24, suchthat when the touch sensing element senses the touching of the biometricfeature on the display device 1, the controlling unit 10 or theprocessing unit 24 may define the touching region of the biometricfeature as a biometric feature identifying region for further detectingthe biometric feature.

FIG. 2 schematically illustrates a top view of a display deviceaccording to this embodiment of the present disclosure. The displaydevice 1 has a display region 1D for displaying image and a peripheralregion 1P that doesn't display image. The peripheral region 1P isdisposed on at least one side of the display region 1D. For example, theperipheral region 1P surrounds the display region 1D. A width of theperipheral region 1P may be also referred to as the border width of thedisplay decide 1. The display element 16 and the sensor element 18 aredisposed in the display region 1D, and the display driver 12, the sensordriver 14 and the processing unit 24 shown in FIG. 1 are disposed in theperipheral region 1P. The regions and the numbers of the gate driver 121and the data driver 122 of display driver 12 and the regions and numbersof the gate driver 141 and the readout driver 142 of the sensor driver14 shown in FIG. 2 are for illustration and not limited thereto. In someembodiments, the number of the gate driver 121 and/or the number of thedata driver 122 may be one or more. In some embodiments, the number ofthe gate driver 141 and/or the number of the readout driver 142 may beone or more.

Specifically, the display device 1 may further include a plurality ofdisplay scan lines 26, a plurality of display data lines 28, a pluralityof sensor scan lines 30, and a plurality of sensor signal lines 32formed on a substrate Sub. The display element 16 includes a pluralityof sub-pixels 161 and a plurality of transistors 162 formed on thesubstrate Sub, in which each sub-pixel 161 is electrically connected toa corresponding transistor 162, and a gate and a source of eachtransistor 162 are electrically connected to the gate driver 121 and thedata driver 122 respectively through a corresponding display scan line26 and a corresponding display data line 28, such that the on/off stateof each transistor 162 can be controlled by display scanning signalsDS1-DSN from the gate driver 121, and the display of each sub-pixel 161can be controlled by display data signals DD1-DDN from the data driver122. In one embodiment, the display element 16 may include at least onetransistor 162 corresponding to one of the sub-pixels 161, for example,if the display element 16 includes at least two transistors 162corresponding to one of the sub-pixels 161, wherein the at least twotransistors 162 could be of a same type or different types, but notlimited thereto. In an example of the transistor of the display element16 electrically connected to the corresponding sub-pixel 161, the numberof the transistor corresponding to one of the sub-pixels may be 1, 3, 4or 7. In another example of the display element 16 including pluraltransistors 162 corresponding to one sub-pixel 161, the pluraltransistors 162 may include a switch transistor and/or a drivingtransistor, but not limited thereto. In some embodiments, the transistor162 “corresponding to” one of the sub-pixels as used herein representsthe transistor 162 is electrically connected to the one of thesub-pixels 161.

Similarly, the sensor element 18 includes a plurality of sensing units181 and a plurality of transistors 182 formed on the substrate Sub, inwhich each sensing unit 181 is electrically connected to a correspondingtransistor 182, and a gate and a source of each transistor 182 areelectrically connected to the gate driver 141 and the driver 142respectively through a corresponding sensor scan line 30 and acorresponding sensor signal line 32, such that the on/off state of eachtransistor 182 can be controlled by sensor scanning signals SS1-SSN fromthe gate driver 141, and the readout driver 142 may receive readoutsignals RS1-RSN from each sensing unit 181. In addition, the sensorelement 18 may include at least one transistor 182 corresponding to oneof the sensing units 181. In another example of the transistor of thesensor element 18 electrically connected to the corresponding sensingunit 181, the number of the transistor may be 2 or 3. In another exampleof the sensor element 18 including plural transistors 182 correspondingto one sensing unit 181, the plural transistors 182 may include areadout transistor, a reset transistor and/or an amplifier transistorbut not limited thereto. The transistor 182 “corresponding to” one ofthe sensing units 181 as used herein represents the transistor 182 iselectrically connected to the one of the sensing units 181. In someembodiments, the transistor 162 and/or the transistor 182 may be athin-film transistor. In some embodiments, type of the transistor 162and/or the transistor 182 may be an amorphous thin-film transistor, alow-temperature polysilicon thin-film transistor, a metal-oxidethin-film transistor, but it is not limited thereto.

In this embodiment, each sensing unit 181 is used to detect light fromthe corresponding sub-pixel 161. For example, the sensing units 181 mayinclude a plurality of sensing units 181 a, a plurality of sensing units181 b, and a plurality of sensing units 181 c, the sub-pixels 161 mayinclude a plurality of first sub-pixel 161 a for emitting light with afirst color, a plurality of second sub-pixel 161 b for emitting lightwith a second color, and a plurality of third sub-pixel 161 c foremitting light with a third color, and each sensing unit 181 a, eachsensing unit 181 b and each sensing unit 181 c correspond to one firstsub-pixel 161 a, one second sub-pixel 161 b and one third sub-pixel 161c respectively. In other words, each sensing unit 181 a can detect thelight having the first color, each sensing unit 181 b can detect thelight having the second color, and each sensing unit 181 c can detectthe light having the third color, in which the first color, the secondcolor and the third color are different from one another, but notlimited thereto. For example, the first color, the second color and thethird color may be respectively red, green and blue, but not limitedthereto. For example, the sensing unit 181 may include a correspondingcolor filter disposed thereon for allowing one color passing through andfiltering light with different colors so as to avoid light interference.In some embodiments, each sensing unit 181 may for example be an optical(such as photo diode) detector, a capacitive detector, a radio frequency(RF) detector, a thermal, piezoresistive detector, an ultrasonicdetector, or a piezoelectric detector, but not limited thereto.

FIG. 3 and FIG. 4 schematically illustrate sectional views of displaydevices according to some embodiments of the present disclosure. In someembodiments shown in FIG. 3, the display device 1A may includeself-emissive display panel, and each of the sub-pixels 161 of thedisplay element 16A may include a light-emitting unit LU. Specifically,the display device 1A may include a display layer 34A formed on thesubstrate Sub and a cover substrate 36 covering and protecting thedisplay layer 34A, in which the display layer 34A may include thelight-emitting units LU of the display element 16A and the sensorelement 18 including a plurality of sensing units 181, and the sensorelement 18 may be formed under the light-emitting units LU, but notlimited thereto. For example, the sensor element 18 is disposed betweenthe light-emitting units LU and the substrate Sub, i.e. thelight-emitting units LU and the sensor element 18 are formed in the samedisplay layer 34A. In a vertical direction VD (top view), the sensingunits 181 may be disposed in the gaps of the sub-pixels 161, such thatthe light from the sub-pixel 161 can be reflected to the correspondingsensing unit 181 by the biometric feature 38, as an arrow shown in FIG.3. The vertical direction VD is defined as being substantiallyperpendicular to a horizontal direction HD. The horizontal direction HDrepresents the horizontal direction of the substrate Sub that isflattened horizontally. In some embodiments, the light-emitting unit LUmay include organic light-emitting diode (OLED), quantum-dot LED (QLED),Mini-LED, Micro-LED or other type light-emitting device. In someembodiments, the sensing units 181 may be formed under the substrateSub, so that the sub-pixels 161 and the sensing units 181 are formed ontwo sides of the substrate Sub (not shown in FIG. 3).

In some embodiments shown in FIG. 4, the display device 1B may includenon-self-emissive display panel. For example, the non-self-emissivedisplay panel is a liquid crystal display panel, and the display layer34B of the display device 1B may include a liquid crystal layer LC, thedisplay element 16B and the sensor element 18 between the substrate Suband a counter substrate 40, in which the liquid crystal layer LC isdisposed between the display element 16B and the sensor element 18.Specifically, the display element 16B is disposed between the liquidcrystal layer LC and the substrate Sub, the sensor element 18 isdisposed between the liquid crystal layer LC and a counter substrate 40,and the sensing unit 181 is disposed above the corresponding transistor(e.g. transistor 162) of the display element 16B. Also, the displaydevice 1B may further include a backlight module BLU disposed under thesubstrate Sub and used for generating a suitable light (such as whitelight). The sub-pixel 161 of some embodiments may include a liquidcrystal controller 1611 for controlling the rotation of the liquidcrystal molecules corresponding to the region of the sub-pixel 161. Forexample, the liquid crystal controller 1611 may be a pixel electrode orother components, but not limited thereto. Thus, light from backlightmodule BLU can penetrate through the sub-pixel 161 and be reflected bythe biometric feature to the corresponding sensing unit 181, as an arrowshown in FIG. 4. For example, the counter substrate 40 may include colorfilters (not shown) for allowing light having different colors to beemitted. In some embodiments, in order to generate light with uniformbrightness, the color filters with different colors may have differentthicknesses. In some embodiments, the display device 1B may optionallyinclude the cover substrate 36 disposed on the counter substrate 40. Insome embodiments, the sensor element 18 may be disposed between thecounter substrate 40 and the cover substrate 36. In one embodiment, thecover substrate 36 can have a touch function, but not limited thereto.

FIG. 5 schematically illustrates a top view of an arrangement of thesub-pixels and the sensing units according to some embodiments of thepresent disclosure. In some embodiments, the arrangement of thesub-pixels 161 may be pentile matrix, and each sensing unit 181 isdisposed between adjacent two of sub-pixels 161. For example, in an oddrow, the first sub-pixels 161 a having first color and the thirdsub-pixels 161 c having third color are alternately arranged along therow direction, and the sensing units 181 and the sub-pixels 161 (such as161 a and 161 c) in the odd row are alternately arranged along the rowdirection. In an even row, the second sub-pixels 161 b having secondcolor are arranged along the row direction, and the sub-pixels 161 (suchas 161 b) and the sensing units 181 in the even row are alternatelyarranged along the row direction. Also, in an odd column, the secondsub-pixels 161 b and the sensing units 181 are alternately arrangedalong the column direction; and in an even column, the first sub-pixels161 a and the third sub-pixels 161 c are alternately arranged along thecolumn direction, and the sub-pixels 161 (such as 161 a and 161 c) andthe sensing units 181 in the odd column are alternately arranged alongthe column direction.

In some embodiments, the first sub-pixel 161 a, the second sub-pixel 161b and the third sub-pixel 161 c may have different areas in a top viewof the display device 1. For example, since the first color, the secondcolor and the third color are red, green and blue respectively, the areaof the third sub-pixel 161 c may be greater than the area of the firstsub-pixel 161 a, and the area of the first sub-pixel 161 a may begreater than the area of the second sub-pixel 161 b. In someembodiments, the sensing units 181 may have different areas in a topview of the display device 1 based on the area difference between thesub-pixels 161. For example, the sensing units 181 arranged in the samerow as the first sub-pixels 161 a and the third sub-pixels 161 c (suchas odd row) may have greater area or less area than the sensing units181 arranged in the same row as the second sub-pixels 161 b (such aseven row). In some embodiments, one of the sensing units 181 between theadjacent first sub-pixel 161 a and the adjacent third sub-pixel 161 cmay be closer to the adjacent first sub-pixel 161 a having the firstcolor than the adjacent third sub-pixel 161 c having the third color. Inother words, since third sub-pixel 161 c emits blue light, which isscattered easier and worse than the red light, to improve the signal tonoise ratio (S/N) of the sensor element 18, a distance W1 between thesensing unit 181 and the adjacent first sub-pixel 161 a is less than adistance W2 between the sensing unit 181 and the adjacent thirdsub-pixel 161 c. The distance W1 is the shortest distance between thesensing unit 181 and the first sub-pixel 161 a adjacent to each other ina row direction RD, and the distance W2 is the shortest distance betweenthe sensing unit 181 and the third sub-pixel 161 c adjacent to eachother in the row direction RD. In some embodiments, any two of thecolors of the first sub-pixel 161 a, the second sub-pixel 161 b and thethird sub-pixel 161 c may be exchanged or may be other colors. In someembodiments, arrangement of the first sub-pixel 161 a, the secondsub-pixel 161 b and the third sub-pixel 161 c may be other kind ofarrangement.

The following description further details a driving method of thedisplay device of the present disclosure. FIG. 6 schematicallyillustrates a flowchart of a driving method of the display device foridentifying the biometric feature according to this embodiment of thepresent disclosure, and FIG. 7 schematically illustrates timingsequences of the display control signal, the sensor control signal, thedisplay scan signal, the sensing scan signal and the readout signal. Thedriving method of the display device includes the following steps and isdetailed accompanying with FIG. 7 as well as FIG. 1 and FIG. 2. In stepS102, the display device 1 starts a sensing time period SP. In thesensing time period SP, the display device 1 starts to detect thebiometric feature. For example, when the sensor element 18 detects thetouching of the biometric feature on the display device 1, thecontrolling unit 10 or the processing unit 24 may start the sensing timeperiod SP for detecting the biometric feature. The condition forstarting the sensing time period SP of the present disclosure is notlimited thereto.

In step S104, the display control signal DC and the sensor controlsignal SC (an enable signal) are respectively provided to the displaydriver 12 and the sensor driver 14 by the control unit 10 or theprocessing unit 24, such that the sensor driver 14 can be activated bythe enable signal from the control unit 10 or the processing unit 24.The duration of the display control signal DC overlaps the duration ofthe sensor control signal SC, such that the display element 16 maygenerate light for biometric feature identification and the sensorelement 18 can detect the reflected light from the biometric feature.For example, the display control signal DC and the sensor control signalSC may be simultaneously provided by the controlling unit 10 or theprocessing unit 24 and be ended at the same time, such that the displaydriver 12 and the sensor driver 14 can be synchronized by thecontrolling unit 10 or the processing unit 24. In some embodiments, thestart time ST1 of the display control signal DC may be earlier than thestart time ST2 of sensor control signal SC. As long as the biometricfeature can be correctly identified, the start time ST1 and the end timeET1 of the display control signal DC and the start time ST2 and the endtime ET2 of the sensor control signal SC can be altered.

Instep S106, after the display driver 12 receives the display controlsignal DC, a display driving signal DDS is transmitted to a displayelement 16 by the display driver 12, and the display element 16 isrefreshed a first predetermined number of times when the sensing element18 is sensing the biometric feature in the sensing time period SP. Inthis embodiment, the first predetermined number of times may range from3 to 120 in the sensing time period SP. In other words, the displaydriving signal DDS may be repeatedly transmitted to the display element16 ranged from 3 to 120 times, such that the sub-pixels 161 may generatelight pulse 3 to 120 times. It is noted that since the display element16 can generate light pulse 3 to 120 times in the sensing time periodSP, the sensor element 18 can receive light 3 to 120 times, therebyaccumulating enough electric charges and improving the S/N ratio and thesensitivity of the sensing units. For this reason, the sensing units 181can be disposed in the display region 1D without reducing the area ofeach sub-pixel 161 or reducing the resolution of the display device 1,i.e. the sensor element 18 can be integrated with the display element 16into the display region 1D of the display device 1, thereby increasingscreen-to-body ratio while providing biometric authentication. Also,even the area of the sensing unit 181 is small, through the increasedrefreshing times, the sensing units 181 still can have good sensitivity.

Specifically, the display driving signal DDS may include a plurality ofdisplay scan signals DS1-DSN transmitted to the display scan line 26respectively and a plurality of display data signals DD1-DDN transmittedto the display data lines 28 respectively. In one frame time FT of thesensing time period SP, the display scan signals DS1-DSN may besequentially transmitted one time, and the display data signals DD1-DDNmay be transmitted according to the display scan signals DS1-DSN, suchthat the sub-pixels 161 can emit the required light pulse one time whilereceiving the display data signals DD1-DDN. When the display element 16is refreshed 3 to 120 times in the sensing time period SP, the displayscan signals DS1-DSN may be sequentially transmitted to the displayelement 16 ranged from 3 to 120 times in 3 to 120 frame times FT. Insome embodiments, adjacent two of the display scan signals DS1-DSN mayoverlap each other or not in one frame time FT. In some embodiment, thefirst predetermined number of times may be 6 to 72 times. In order tohave short unlocking time, the first predetermined number of times maybe decreased based on the frame time FT. For example, when therefreshing rate (frequency) of the display device 1 is 60 Hz (i.e. theframe time FT is 0.0167 seconds, the first predetermined number of timesmay be 6, 18 or 30. When the refreshing rate (frequency) of the displaydevice 1 is 120 Hz (i.e. the frame time FT is 0.0083 seconds less than0.0167 seconds), the first predetermined number of times may beincreased to be 12, 36 or 60.

In step S108, after the sensor driver 14 receives the sensor controlsignal SC, a sensor driving signal SDS is transmitted to the sensorelement 18 by the sensor driver 14, and the sensor element 18 isrefreshed a second predetermined number of times in the sensing timeperiod SP. In this embodiment, as shown in FIG. 7, the secondpredetermined number of times may be one. Specifically, the sensordriving signal SDS may include a plurality of sensor scan signalsSS1-SSN and a plurality of readout signals RS1-RSN. When the sensorelement 18 is driven once, the duration of the sensor scan signalsSS1-SSN may overlap all the frame times FT of the display element 16.The readout signals RS1-RSN may be received by the readout driver 142near the end time of the sensor scan signals SS1-SSN. The duration ofthe readout signals RS1-RSN may overlap at least one frame time FT ornot. In some embodiments, the second predetermined number of times maybe plural, so the electric charges converted by the sensing units 181can be read out plural times in one sensing time period SP by thereadout driver 142, and the readout signals RS1-RSN received by thereadout driver 142 more than one times in one sensing time period SP canbe accumulated by the sensor driver 14 to increase the S/N ratio. Insome embodiments, the sensor element 18 of the display device 1 mayperform more than one times to detect the biometric feature in more thanone sensing time periods SP.

FIG. 8 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure. Forclarity, the arrangement of the sub-pixels mentioned in the followingembodiments takes pentile matrix for an example, and sensing units arenot shown, but not limited thereto. In some embodiments, all thesub-pixels 161 having the same color are turned on repeatedly, and theremaining sub-pixels having different colors are turned off in onesensing time period, so as to display one frame in each frame time. Forexample, all the second sub-pixels 161 b having the second color aredriven and turned on repeatedly to sequentially generate the frames(e.g. a first frame F1A, a second frame F2A, etc.) while the firstsub-pixels 161 a and the third sub-pixels 161 c are turned off, so as togenerate light having the same second color in each frame time. Thus,the sensing units 181 corresponding to the second sub-pixels 161 b maydetect the light having the second color without being interfered byother color light, thereby increasing the sensitivity of the sensingunits 181. For example, a circle shown in FIG. 8 may represent a regionof reflected light from each second sub-pixel 161 b. In someembodiments, all the sub-pixels 161 turned on in each frame FA may alsobe all the first sub-pixels 161 a or all the third sub-pixels 161 c. Inone embodiment, a region shape of a reflected light from one sub-pixel161 may be a circle, a polygen or a free-shape, but not limited thereto.In some embodiments, an area of the region is not limited to thedrawings in the figures and also could be adjusted to a suitable size,but not limited thereto.

FIG. 9 schematically illustrates sub-pixels turned on in different frametimes according to some embodiments of the present disclosure. In someembodiments, a first group G1 of the sub-pixels 161 and a second groupG2 of the sub-pixels 161 are turned on sequentially and alternately, andthe remaining sub-pixels 161 are turned off in the sensing time periodSP, in which the sub-pixels 161 in first group G1 are different from thesub-pixels 161 in the second group G2. Specifically, the first group G1of the sub-pixels 161 is turned on to display one frame F1B in one frametime, and then the second group G2 of the sub-pixels 161 is turned on todisplay another frame F2B in another frame time, in which the firstgroup G1 of the sub-pixels 161 and the second group G2 of the sub-pixels161 may have the same color. As an example, the second sub-pixels 161 bmay be the sub-pixels 161 turned on in the sensing time period. Thesecond sub-pixels 161 b in the first group G1 are not adjacentsub-pixels 161, so the distance between the adjacent second sub-pixels161 b in the first group G1 can be increased, thereby reducing theinterference of reflected light from different second sub-pixels 161 b,as the circles shown in FIG. 9. Similarly, the second sub-pixels 161 bin the second group G2 may prevent the interference of different secondsub-pixels 161 b. For example, one of the second sub-pixels 161 b in thefirst group G1 may be disposed between adjacent two of the secondsub-pixels 161 b in the second group G2. In other words, the secondsub-pixels 161 b in the first group G1 and the second sub-pixels 161 bin the second group G2 are respectively arranged in staggered pattern,and in each even row, each second sub-pixel 161 b in the first group G1and each second sub-pixel 161 b in the second group G2 are alternatelyarranged.

FIG. 10 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure. Insome embodiments, as compared with FIG. 9, the first group G1 of thesub-pixels 161 and the second group G2 of the sub-pixels 161 turned onsequentially may have different colors. Specifically, the first group G1of the sub-pixels 161 having one color is turned on to display one frameF1C of one frame time, and the second group G2 of the sub-pixels 161having another color is then turned on to display another frame F2C ofanother subsequent frame time while the remaining sub-pixels 161 areturned off. In some embodiment, after the frame F2C, a third group G3 ofthe sub-pixel 161 of the same color as the first group G1 may be turnedon to display another frame F3C of another subsequent frame time, andthen the second group G2 of the sub-pixels 161 is turned on to displayanother frame F4C of another subsequent frame time, so the first groupG1 of the sub-pixels 161, the second group G2 of the sub-pixels 161, thethird group G3 of the sub-pixels 161 and the second group G2 of thesub-pixels 161 are turned on alternately. As an example, a part of thesecond sub-pixels 161 b may be the first group G1 of the sub-pixels 161,other part of the second sub-pixels 161 b may be the third group G3 ofthe sub-pixels 161, and all the first sub-pixels 161 a may be the secondgroup G2 of the sub-pixels 161. The second sub-pixels 161 b in the firstgroup G1 may be the same as the first group G1 shown in FIG. 9, and thesecond sub-pixels 161 b in the third group G3 may be the same as thesecond group G2 in FIG. 9, so the patterns of the second sub-pixels infirst group G1 and third group G3 will not be detailed redundantly.Through alternately turning on the first group G1, the second group G2,the third group G3 and the second group G2, the frames F1C, F2C, F3C,F4C can be alternately generated. It is noted that through alternatelyturning on the groups of the sub-pixels with different colors, moresensing units can be used to detect the biometric feature, andinterference of reflected light from different sub-pixels 161 b ofdifferent colors may still be reduced.

In some embodiments, the first group G1 of the sub-pixels 161 may be allthe sub-pixels 161 having the same color (e.g. the second sub-pixels 161b), the second group G2 of the sub-pixels 161 may be all the sub-pixels161 having another color (e.g. the first sub-pixels 161 a), and thefirst group G1 and the second group G2 may be alternately turned on todisplay the frames F1C, F2C alternately.

FIG. 11 schematically illustrates the sub-pixels turned on in differentframe times according to some embodiments of the present disclosure. Insome embodiments, the first group G1 of the sub-pixels 161 and thesecond group G2 of the sub-pixels 161 that have different colors may beturned on at a same time. Specifically, the first group G1 of thesub-pixels 161 having one color and the second group G2 of thesub-pixels 161 having another color are turned on to display one frameF1D of one frame time while the remaining sub-pixels 161 are turned off.In some embodiments, after the frame F1D, a third group G3 of thesub-pixel 161 having the same color as the first group G1 and the secondgroup G2 may be turned on to display another frame F2D of anothersubsequent frame time, so the frames F1D, F2D may be displayedalternately. As an example, apart of the second sub-pixels 161 b may bethe first group G1 of the sub-pixels 161, and other part of the secondsub-pixels 161 b may be the third group G3 of the sub-pixels 161, andall the first sub-pixels 161 a may be the second group G2 of thesub-pixels 161. The second sub-pixels 161 b in the first group G1 may bethe same as the first group G1 shown in FIG. 9, and the secondsub-pixels 161 b in the third group G3 may be the same as the secondgroup G2 in FIG. 9, so the patterns of the second sub-pixels in firstgroup G1 and third group G3 will not be detailed redundantly. Forexample, the first sub-pixels 161 a have one of red and green, and thesecond sub-pixels 161 b have the other one of red and green.

In some embodiments, after the frame F1D, the first group G1 of thesub-pixels 161 having one color and the second group G2 of thesub-pixels 161 having another color may be repeatedly turned on todisplay another frame F2D in next frame time. In some embodiments, allthe second sub-pixels 161 b may be the first group G of the sub-pixels161.

As mentioned above, the display device can generate light pulse 3 to 120times in the sensing time period, so the sensor element can receivelight 3 to 120 times to accumulate enough signals and improve the S/Nratio and the sensitivity of the sensing units. For this reason, thesensor element can be integrated with the display element into thedisplay region of the display device without reducing the area of eachsub-pixel or reducing the resolution of the display device, therebyincreasing screen-to-body ratio while providing biometricauthentication.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the disclosure. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A display device, comprising: a controlling unit; a display driver electrically connected to the controlling unit; a sensor driver electrically connected to the controlling unit; a display element electrically connected to the display driver; and a sensor element electrically connected to the sensor driver; wherein when the sensor element is sensing a biometric feature in a sensing time period, the display element is refreshed by the display driver 3 to 120 times in the sensing time period.
 2. The display device according to claim 1, wherein the display element is refreshed by the display driver 6 to 72 times in the sensing time period.
 3. The display device according to claim 1, wherein the sensor element is refreshed at least one time in the sensing time period.
 4. The display device according to claim 1, wherein the display element comprises a plurality of sub-pixels having a same color, and all the plurality of sub-pixels are turned on repeatedly in the sensing time period.
 5. The display device according to claim 1, wherein the display element comprises a plurality of sub-pixels 161, and a first group of the plurality of sub-pixels and a second group of the plurality of sub-pixels are turned on sequentially.
 6. The display device according to claim 5, wherein the first group of the plurality of sub-pixels and the second group of the plurality of sub-pixels have a same color.
 7. The display device according to claim 5, wherein the first group of the plurality of sub-pixels have a first color, and the second group of the plurality of sub-pixels have a second color different from the first color.
 8. The display device according to claim 7, wherein a third group of the plurality of sub-pixels having the first color, and the first group of the plurality of sub-pixels, the second group of the plurality of sub-pixels, the third group of the plurality of sub-pixels and the second group of the plurality of sub-pixels are turned on alternately.
 9. The display device according to claim 1, wherein the display element comprises a plurality of sub-pixels, a first group of the plurality of sub-pixels has a first color and a second group of the plurality of sub-pixels has a second color different from the first color, and the first group of the plurality of sub-pixels and the second group of the plurality of sub-pixels are turned on at a same time.
 10. The display device according to claim 9, wherein a third group of the plurality of sub-pixels has the first color, and the first group of the plurality of sub-pixels and the third group of the plurality of sub-pixels are turned on sequentially.
 11. The display device according to claim 1, wherein the sensor driver is activated by an enable signal from the controlling unit.
 12. The display device according to claim 1, wherein the display driver and the sensor driver are synchronized by the controlling unit.
 13. The display device according to claim 1, further comprising a processing unit, wherein the processing unit is electrically connected to the controlling unit, the display driver, and the sensor driver respectively, and the processing unit, the display driver and the sensor driver are integrated in a single integrated circuit.
 14. The display device according to claim 1, wherein the display element comprises a first sub-pixel having a first color and a second sub-pixel having a second color different from the first color, the sensor element comprises a sensing unit disposed between the first sub-pixel and the second sub-pixel, and a distance between the sensing unit and the first sub-pixel is less than a distance between the sensing unit and the second sub-pixel.
 15. The display device according to claim 1, wherein the display element comprises a first sub-pixel having a first color and a second sub-pixel having a second color different from the first color, and an area of the first sub-pixel is different from an area of the second sub-pixel.
 16. The display device according to claim 1, wherein the sensor element comprises a plurality of sensing units, and the plurality of sensing units have different areas in a top view of the display device.
 17. The display device according to claim 1, wherein the display element comprises a plurality of light-emitting units, and the sensor element is disposed under the plurality of light-emitting units.
 18. The display device according to claim 1, further comprising a liquid crystal layer disposed between the display element and the sensor element.
 19. A driving method of a display device, comprising: providing a display control signal to a display driver and a sensor control signal to a sensor driver by a controlling unit; transmitting a display driving signal to a display element by the display driver; and transmitting a sensor driving signal to a sensor element by the sensor driver, wherein when the sensor element is sensing a biometric feature in a sensing time period, the display element is refreshed by the display driver 3 to 120 times in the sensing time period.
 20. The driving method of the display device according to claim 19, wherein the display element is refreshed by the display driver 6 to 72 times in the sensing time period. 